This invention pertains to quick locking fasteners. More particularly, this invention pertains to quick engaging fastening nuts for engaging threaded portions of bolts, clamps, pipe fittings and the like.
Quick locking fastening nuts have been available for various purposes in the past. The objective of a quick locking fastening nut is to be able to transitionally slide the fastening nut on a bolt or threaded member without the necessity of rotation until the fastening nut is in substantial final engagement against andn abutment surface of the head of the bolt. A wrench or other tool is used to tighten the fastening nut during its final rotational engagement. This is achieved by a wedging action which causes a tightening of a segmented internally threaded insert set in the nut casing. The segments are spread apart by the threads of a bolt inserted through the threaded aperture defined by the segments, allowing the bolt to be pushed through by translational movement. However, the segments are sufficiently confined within the nut casing to allow the nut segments to grasp the threads when rotated into engagement.
In the prior art, one type of self locking nut uses a segmented insert set in a casing cavity. The insert set has a frustoconical exterior surface. The tendency of a bolt or threaded member acting against the threads of the insert of this device is to cause an uneven spread of the insert segments and applying uneven and excessive on the threads. As a result, self locking nuts such as these have been unable to fasten adequately.
U. S. Pat. No. 5,100,275, which issued Mar. 31, 1992 to the present inventor discloses a quick locking fastener that includes a fastening nut which has a casing having an internal cavity defining a central axis. The cavity has a segmented insert set comprising a plurality of mating insert segments disposed within the cavity of the casing. The insert set defines an annular substantially contiguous yet spreadable interior thread for mating with the threads of a threaded member such as a bolt. The exterior surface of the insert set has a first annular bevel surface adjacent a forward portion of the casing, and a second annular bevel surface of greater maximum radius than the first annular beveled surface which is positioned coaxial, parallel and spaced from the first annular bevel surface. The first and second bevels are at substantially the same angle to the central casing axis. First and second annular inclined surfaces on the interior surface of the casing abut the first and second bevel surfaces of the insert segments in sliding engagement. The first and second annular inclined surface allow the segments to be outwardly guided by spreading of the segments during translational movement by a threaded member, and inwardly pulled forward to centrally grasp the thread of a threaded member when rotated towards a fully engaged position. This provided generally balanced radial forces against the threads of a threaded member and the internal threads of the insert segments. Additional features of this device include a circular spring adjacent the rear of the insert segments, disposed about a bevel surface on an end cap. An annular retaining ring having plural inwardly directed tangs engages the insert segments to prevent rotation of the insert segments. A lock ring disposed intermediate the retaining ring and the interior of the end cap provides torque limiting, whereby the segments can rotate when the torque exceeds a predetermined design force.
U. S. Pat. No. 5,378,100, issued Jan. 3, 1995 to Fullerton discloses a rapidly engaging and disengaging threaded coupling fastener that includes a first member provided with external threads and a second member having an opening into which the first member is inserted. The second member is provided with a plurality of movably mounted internally threaded elements for receiving the external threads of the first member. The first member may be inserted into the second member by rectilinear sliding movement, after which the first member is rotated into tight engagement with the second member. Release of the first member is accomplished by rotating the first member very slightly in the opposite direction, after which simple manual manipulation of the second member withdraws the threaded elements from engagement, permitting the first member to be slidably removed from the second member.
The present invention provides a quick locking fastener assembly that has a simpler and stronger structure than previous devices. The quick locking fastener assembly according to the present invention includes a housing, two or more threaded inserts and an integral retainer ring and end cap. A spring may be included to bias the inserts toward the bolt insert opening and to provide torque limiting.